Suzuki dt200 magneto explode?

[Stormforce6.5]

Hi, just wondering if anyone has any heard of this happening? I have a dt200, driving perfectly, whilst driving the positive terminal on the battery came loose so when I tried to restart it sparked, tightened up the connection and started no problem but when I accelerated nothing happened! When I took the cover off I noticed shards of magnetic material, looks like graphite, littered around the engine bay, only thing I can think of is a magnet must've exploded? Anyone have any info please!!

[boats.net]

Haven't had it happen but possible magnets in flywheel came loose due to stator overheating.